Generally, in a digital transmission system, an information signal is converted into digital data including, as representative thereof, a plurality of bits differing in significance from each other. The plurality of bits are transmitted through a transmission path or recorded on a recording medium. Transmission problems, such as noise, interference, and drop out, results in errors in the received or reproduced digital data. The extent of the transmission problem depends upon the significance of the bit which is subjected to the transmission problem. For example, if the transmission problem occurs in the least significant bit (LSB), an error is produced of V/2.sup.n, wherein V is the maximum amplitude of the information signal and n is the number of bits representing the information signal. In this case, since the error is relatively low, the transmission problem is extremely limited and causes little or no transmission degradation. On the other hand, if a transmission problem occurs in the most significant bit (MSB), an error is produced of V/2. This error is equal to one-half the maximum amplitude of the information signal and in this case a serious transmission degradation results.
To reduce transmission errors, in the prior art, conversion systems for converting the information signal into specified codes, or additional bits for checking the errors are added to the data bits. This makes the digital transmission system more complicated.
It is, therefore, an object of this invention to provide a digital transmission system in which information signals are relatively unaffected by transmission problems.
It is a further object of this invention to provide a digital transmission system which does not require the use of a specified conversion system or additional bits to reduce transmission errors.